Antibodies are natural proteins that the vertebrate immune system forms in response to foreign substances (antigens), primarily for defense against infection. For over a century, antibodies have been induced in animals under artificial conditions and harvested for use in therapy or diagnosis of disease conditions, or for biological research. Each individual antibody producing cell produces a single type of antibody with a chemically defined composition, however, antibodies obtained directly from animal serum in response to antigen inoculation actually comprise an ensemble of non-identical molecules (e.g., polyclonal antibodies) made from an ensemble of individual antibody producing cells.
Antibody fusion constructs can be used to improve the delivery of drugs or other agents to target cells, tissues and tumors. Antibody fusion constructs may comprise a chemical linker to attach a drug or other agent to antibody. Exemplary antibody fusion constructs and methods of producing antibody fusion constructs are disclosed in US patent application numbers 2006/0182751, 2007/0160617 and U.S. Pat. No. 7,736,652.
Disclosed herein are novel immunoglobulin fusion proteins and methods of producing such immunoglobulin fusion proteins. Further disclosed herein are uses of the immunoglobulin fusion proteins for the treatment of various diseases and conditions. Methods of extending the half-life of a therapeutic agent are also disclosed herein.